title: Manual disfluency in drawing while producing and listening to disfluent speech.
abstract: This study investigated the extent to which manual fluency was associated with speech fluency in fluent speakers engaged in dual motor tasks. Thirteen right-handed adult females repeatedly drew circles with a pen on a digitizer tablet under five conditions: (1) a baseline (without reading or listening to speech), (2) reading fluently, (3) reading disfluently, (4) listening to fluent speech, and (5) listening to disfluent speech. The primary measure of disfluency was normalized mean squared jerk (NJ) in the pen strokes. Pen stroke time (ST) and pressure (PP) were also measured. NJ of the circle movements was significantly increased in both the disfluent reading and the disfluent listening conditions (p<0.05), compared to the baseline condition. In the fluent listening and reading conditions, NJ in circle drawing was unaltered compared to the baseline condition. Relative to baseline, ST increased significantly (p<0.05), but to a similar extent in all experimental conditions. Significantly (p<.05) greater pen pressure were also found in the disfluent versus fluent conditions. Positive correlations (r=0.33-0.63) were found between NJ and ST across conditions. These findings demonstrate that in dual-tasks, speech fluency can influence manual fluency. This is consistent with the corpus of data showing neural connectivity between manual and speech tasks, as well between perception and production. The mirror neuron system is implicated as a mechanism involved in forging these links.
authors.affiliation: Department of Speech-Language Pathology, Seton Hall University, South Orange, NJ 07079, USA.
authors.forename: Vikram
authors.initials: V
authors.lastname: Dayalu
authors.forename: Hans-Leo
authors.initials: HL
authors.lastname: Teulings
authors.forename: Andrew
authors.initials: A
authors.lastname: Bowers
authors.forename: Stephen
authors.initials: S
authors.lastname: Crawcour
authors.forename: Tim
authors.initials: T
authors.lastname: Saltuklaroglu
mesh_terms: D000328:Adult; D001154:Art; D001288:Attention / Q000502:physiology*; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D006225:Hand / Q000294:innervation; D006801:Humans; D009048:Motor Skills / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation; D009415:Nerve Net / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D011932:Reading; D013018:Sound Spectrography; D013067:Speech Perception / Q000502:physiology*; D013342:Stuttering / Q000503:physiopathology; D014705:Verbal Behavior / Q000502:physiology*
keywords: Disfluency; Dual task; Hand movement; Pen pressure; Speech; Stroke time; Stuttering